1. Field of the Invention
The present invention relates to an indication display unit for vehicles which provides a driver with the whole information concerning its navigation such as its velocity, revolution frequency of the engine, left-fuel quantity, clock, and other various alarm devices in use of an indication projector for projecting image to the surface of a reflecting means which is located in front of a driver seat.
2. Description of the Prior Art
Conventionally, widely used indication display unit for vehicles comprise a semi-translucent mirror as a reflecting means located on the top surface a dashboard in front of a windshield, so that above mentioned various indications are projected thereto so as to enable a driver to sight a virtual image therebehind ahead of the windshield.
The indication display unit of this type is called a head-up display (hereinafter referred to as "HUD"), and is used for saving space for installation of increasing number of display devices or for raising the safety level by providing the driver with various driving information during the vehicle is moving at high speed.
However, since the above semi-translucent mirror is fixedly upright on the dashboard according to the conventional device, not only it is effective only when a vehicle is moving at low speed in which case the driver can sight the speed meter located in the normal instrument panel position, but it can also be a great nuisance as it is fixed just in front of the driver.
For example, FIG. 15 shows two indicating states in a conventional device. FIGS. 15a and 15b show the cases when the vehicle speed is 188 Km/h, and when it is 5 Km/h respectively.
The visual field of the driver varies according to the vehicle's moving speed. For example, as shown in dashed lines in FIG. 15, the visible range A' when its moving speed is low (shown in FIG. 15b) becomes wider than the other range A realized when it is high (shown in FIG. 15a). Therefore, the driver is not disturbed by the reflecting means 14 when the vehicle is moving at high speed since the displayed image B reflected thereon is sighted outside but near the range A, but when at low speed, the driver feels annoyed at the existence of the reflecting means 14 since the displayed image B' is located within the visible range A', and consequently the only thing the driver can is to put up with it.
There is also another problem that conventional type reflecting means easily gets dirt because it is fixedly located on the dashboard, whereby so as to acquire the clear image it should be cleaned all the time.
Thus the principal object of the present invention is to provide an indication display unit for vehicles equipped with a reflecting means shifting means, whereby it can be put away outside the driver's visual field while the image projected from an indication projector is not required.